Testing device for the ultrasonic inspection of barstock

ABSTRACT

The invention relates to a test device for the ultrasonic testing of strand material, comprising a) a stationary container that defines a substantially cylindrical interior space that has a larger diameter than the strand material and that has a cylinder axis, and b) a device for producing a peripheral water jacket that is associated either with at least one nozzle for a water feed disposed substantially tangential to an inner surface of the interior space and leading to said interior space, and/or with a bucket wheel that rotates about the cylinder axis and that is provided with a drive unit, and c) at least one ultrasonic probe that is linked with the container and that has an active surface that is freely accessible from the cylindrical interior space.

The invention relates to a testing device for the ultrasonic inspectionof barstock. Such type testing devices are known in a variety ofrealizations; by way of example the reader is referred to the DE-book“Werkstoffprüfung mit Ultraschall” (“Material Inspection withUltrasounds”), 4^(th) edition, by the authors J. Krautkrämer & H.Krautkrämer.

The inspection of barstock more specifically involves detection ofinternal flaws and of surface flaws but also comprises the testing ofthe dimensions. It is known that for ultrasonic inspection a water pathis to be provided and maintained between the ultrasonic probe and thebar to be tested. Several techniques are known to achieve this such ase.g., immersion testing, partial immersion testing or inspection bymeans of a guided water jet. Further, closed water tanks exist, whichare often termed SPS and through which the test samples are conveyed.After the test sample has entered the closed water tank, the test sampleseals the tank inlet and outlet. The water tank is filled with water inorder to achieve the coupling between the probe and the test sample. Theprobes may thereby be disposed in a circumferential symmetry. Thedisadvantage thereof is the quite long time needed for the tank to befilled with water, end portions remaining untreated. Further, airbubbles in the coupling water compromise the inspection.

Rotary testing devices are moreover known. Rotation of the entiretesting chamber together with the probes permits to generate a stablewater jacket. Through sealing systems disposed on the inlet and on theoutlet side a substantially tubular water jacket through which the testsamples can be conveyed is obtained. This type of testing technique hasa high testing efficiency but also involves high mechanical expensebecause of the rotating testing chamber. The term “barstock” is to beconstrued herein after as any kind of elongated material, morespecifically round steel bars, bars with non round profiles such assquare and hexagonal bars, flat material in the form of rods, but alsotubes and rolling stock, extruded profiles.

It is the object of the invention to indicate a device for theultrasonic inspection of barstock that has the advantages of the abovementioned rotary testing device but which is mechanically simple inconstruction, which requires little preparation prior to ultrasonicinspection and in which the probes can be disposed anywhere on thecircumference.

This objective is accomplished by a testing device for the ultrasonicinspection of barstock a) with a stationary tank defining asubstantially cylindrical interior space that has a larger diameter thanthe barstock and is provided with a cylinder's axis, b) with anequipment for producing a surrounding water jacket, said equipment beingprovided with either at least one nozzle for a water supply which isdisposed in substantially tangential contact with an inner lining of theinterior space into which it discharges and/or a blade wheel that isdisposed so as to rotate about the cylinder's axis and that is assigneda rotary drive mechanism and c) with at least one ultrasonic probe thatis connected to the tank and has an active face which is freelyaccessible from the cylindrical interior space.

Water is introduced through the nozzle which is in tangential contactand discharges into the interior space of the tank. Through this supplyline and the resulting rotational movement of the water a substantiallytubular water jacket is obtained. Unwanted air bubbles do not remainstationary but are swept along and are therefore insignificant intesting. The tank does not rotate, it rather remains stationary. Whatrotates though is the water jacket within the tank. As the water jacketrotates it is stable so that testing may be carried out immediatelyafter a test sample in the form of a bar has entered. The rotating waterjacket may be as well produced by the blade wheel. The term “bladewheel” is to be construed as any arrangement of blades, which areoriented in a more or less radial direction, that is capable of movingthe water within the tank in such a manner that the revolving waterjacket is obtained. The blade wheel is preferably disposed on frontfaces. It may be substituted for the front faces. The blade wheels arepreferably positioned outside the ultrasound path of the at least oneultrasonic probe. It is also possible though that the ultrasonic probesemit sound energy through the range of movement of the blades of a bladewheel. In this case, they are matched to the movement of the blade wheelin such a manner that a measurement only occurs when there is no bladewheel in the ultrasound path.

The tank may have a very short structure. Untested end portions remainsmall. It is however also possible to perform the final testing insidethe tank if there is an end region of a bar to be tested in the interiorspace.

At least one ultrasonic probe is disposed on the tank, a great multitudeof probes is preferably provided for. They can be disposed anywhere onthe circumference. Probe clusters or probe arrays can also be utilized.Accordingly, they can be oriented radially or inclined at any anglewithin the possible ultrasonic emission angles, e.g., inclined in theradial plane or at an angle different from 90 degrees to the cylinder'saxis.

The ultrasonic probes have an active face that is preferably formed by aleading body made from an appropriate solid material. Said leading bodymay be formed in such a manner that it is made flush with the tank,i.e., that it does not impair the rotation of the water within thetubular tank.

The parts to be tested are conveyed through the interior space in adirection that is substantially concentric with the cylinder's axis. Itis however also possible to inspect stationary bars or profiles byhaving the tank made from two shells that are to be joined together inan axial plane, are placed around a stationary bar, a tube for example,and can be axially displaced in order to perform the inspection.

Guide means for the barstock are provided on the two front faces of thetubular tank and are devised for guiding the bar to be tested so thatthe bar to be tested is positioned in such a manner that it issubstantially concentric with the cylinder's axis. Suited sealing meansare preferably provided for keeping the exit of water in the region ofthe front faces low. It is however also possible to deliberately havethe water exiting in the region of the front faces so that the seals canbe very simple or even dispensed with on the one side and that noseparate outlet is required on the other side. A separate outlet may beprovided for though, said outlet being configured according to the atleast one nozzle for water supply and allowing the water to exittangentially in the direction of rotation.

For sealing the region of the front faces, replaceable end rings thatcan be readily removably fastened to the two front faces of the tankhave proved particularly efficient. They exist in various realizations,i.e., with differing central openings that are adapted to the respectiveone of the barstock to be tested, namely to the profile thereof.

In the region of the front faces, at the site where the end rings aredisposed, water may, possibly is even intended to, exit. Collectingbasins for collecting the exiting water are therefore disposed beneaththe front faces.

Further advantages and characteristics of the invention will becomeapparent from the other claims and from the following non restrictivedescription of embodiments of the invention, given by way of exampleonly with reference to the drawing in which:

FIG. 1: is an axial lengthwise section through a testing deviceaccording to the invention with a round bar to be tested,

FIG. 2: is a sectional view of the device according to FIG. 1 along theline II—II,

FIG. 3: is an axial sectional view showing a testing device with aconical inner lining,

FIG. 4: is an axial side view of an openable testing device,

FIG. 5: is an axial side view of a guide bush composed of twosemi-annular halves that may be assembled,

FIG. 6: is another embodiment of a testing device in an illustrationaccording to FIG. 1 with a square bar to be tested and

FIG. 7: is a sectional view similar to the illustration according toFIG. 2 for an embodiment similar to that of FIG. 6.

FIG. 1 shows a testing device for the ultrasonic inspection of barstockaccording to the invention. The device has a tubular tank 20 having asubstantially cylindrical interior space 22. It further has two frontfaces 24 that are each closed by a guide bush 26 being annular in shapeso as to leave an opening for the passage of the barstock to be tested.

In the embodiment according to FIG. 1 and FIG. 2 the barstock to betested is a bar 28 in the form of a round rod that closely fits insealing means of the two guide bushes 26 and is guided through saidguide bushes. It can be transported in the direction of the arrow 30.

A nozzle 32 for the water supply discharges into the interior space 22.As shown in FIG. 2, another nozzle having the same direction is offsetby 180 degrees relative thereto. These nozzles 32 are disposed in such atangential contact with the inner lining that they introduce the watersubstantially tangentially. A rotating tubular water jacket, as it canbe surveyed from FIG. 2, is thus formed. It revolves around the bar 28to be tested in the direction of the arrows 31.

For the actual ultrasonic testing, three probes 34 are disposed on thetank 20, said three probes being indicated by way of example only andrepresenting the possible probes. A probe emits ultrasound energy on aradial line, another at an angle to the longitudinal axis 36, a third ona radial plane, but not through the center, meaning not through thelongitudinal axis 36. Each of the ultrasonic probes 34 has an activeface 38 that protrudes into the interior space and is made as flush aspossible with the inner lining to the shape of which it conforms. Forthis purpose, the angle beam probe 34 has a substantially wedged leadingmember.

The probes as well as the associated, well known test electronics, whichhas not been discussed in greater detail herein and which corresponds tothe state of the art, are devised for the pulse echo technique. Otherinspection methods are also possible. The reader is referred in thisrespect to the book mentioned herein above.

In the exemplary embodiment according to the FIGS. 1 and 2, the waterused for coupling exits in the region of the guide bushes 26, morespecifically between the guides bushes 26 and the bar 28, and iscollected in collecting basins 40 from where it is evacuated.

The radial thickness of the water jacket between bar 28 and inner lining22 amounts to at least 5 millimeters, it preferably amounts to somecentimeters. The flow rate in the direction of rotation is chosen to besuch that any kind of bubbles is swept along and that in any case theyare not allowed to get trapped somewhere.

The probes 34 can be disposed in a circumferential symmetry on the tank20. The arrangement depends on the construction of the testing deviceand can be adapted to the specific inspection requirements.

The tank 20 may be quite short, its axial length needs only be longenough to accommodate all of the probes for the inspection to be carriedout.

The mechanical structure of the testing device is quite simple, thereare no rotating parts, the only rotating element is the water jacket.

FIG. 3 shows a tank 20 with a slightly conical interior space 22. Inthis case, the water is introduced through a nozzle 32. It is located inthe region with the greater diameter. The water leaves the interiorspace 22 at an outlet nozzle 42 that is similar in construction anddisposed in the same direction. Independent thereof, ridges of a smallheight ranging for example from 5 to 10 mm are provided that arehelically arranged on the inner lining 22 and that serve as guidingplates 44 which are helically arranged on the periphery thereof. Theylead the water jacket on a helical path from the inlet to the outlet.

FIG. 4 shows a tank that is divided, in a plane passing through thelongitudinal axis 36, into two shells that are joined together by ajoint 46 with an articulation axis that is oriented parallel to thelongitudinal axis 36 in such a manner that they can be folded togetherto form a tank according to FIGS. 1 and 2. Corresponding sealing meansare provided on the two shells 50, 52. With the appropriate guide bushes26, said tank 20 can be utilized for inspecting stationary bars, i.e.,such bars 28 that are already installed such as tubes in chemical ornuclear plants.

The arrows 48 show how the two shells 50, 52 can be folded together toform a closed tank.

Finally, FIG. 5 shows a guide bush 26 that in the present case iscomposed of two segments. As a result thereof, the guide bush 26 can beplaced onto bars without the ends thereof having to be threaded throughor onto stationary, already installed bars in the manner describedherein above in connection with the embodiment according to FIG. 4.

To provide a seal against the bars 28, seals 43 are provided on theguide bushes 26, see FIG. 3. The guide bushes 26 can be placed intosuited recesses or seats provided on the front faces 24 of the tank 20in such a manner that they closely fit therein and are readily removabletherefrom.

Guide bushes 26 with adjustable openings also proved efficient, e.g.,such with an iris diaphragm similar to those known from cameras. Withround test samples in particular, it is advantageous to rotate the testsample as it is being conveyed through the testing device. In this way,the local resolution can be improved. A rotating device takes hold ofthe test sample and rotates it relative to the testing device. Thetesting device may also be pivoted back and forth, e.g., be rotated 360degrees back and forth about the longitudinal axis 30. The testingdevice according to the invention is suited for such applications inwhich a flaw detected during normal testing or a discrepancy aresubsequently examined more closely by moving or rotating the test sampleback and forth in such a manner that test sample and/or testing deviceare moved about the site of the detected flaw in a special test runwhich permits improved and more specific measurement and detection ofthe flaw.

In the embodiment according to the FIGS. 6 and 7, the water (or anotherfluid) inside the cylindrical interior space 22 of the tubular tank 20is brought to rotate in the direction indicated by the arrows 31 (FIG.7) by way of two blade wheels 54. The blade wheels 54 are arranged onthe front faces and replace these. Bearings 56 for rotatably carryingthe blade wheels 54 are provided for this purpose. The blade wheels 54have a number of individual blades 58 that are substantially located inone diametral plane. There is a lot of space between the various blades58 so that ultrasound measurement can be carried out between two blades58 in the case that the blade wheels 54 are not located completely outof the range of movement of the blade wheels 54 as shown in FIG. 6 forexample.

The blade wheels 54 are driven by an engine 60 disposed outside. Forthis purpose, an engine axis extends across the side part and ends in apinion. The pinion engages in a toothed ring cooperating with the bladewheel 54. Other driving devices for driving the blade wheel 54 arepossible. It is also possible to arrange or to mount the blade wheels 45on the housing 20. The blades 58 shown are connected to an annular discfrom which they protrude in the direction counter to the bearing 56. Theengine 60 can also be disposed in the housing. As many blades 58 and asmany blade wheels 54 as are necessary to form the water jacket wantedare provided for.

FIG. 6 shows the inspection of an end portion of a bar 28 with asubstantially square cross section (see FIG. 7). The right front face isclosed. It can be provided with a passage for the bar 28, which alsoapplies to the left front face.

It is possible to combine the movement of the water by tangentiallyintroducing the water, see FIGS. 1 and 2, on the one side and driving itby means of a blade wheel 54 on the other side.

What is claimed is:
 1. A testing device for the ultrasonic inspection ofbarstock material having a cross-sectional dimension, the testing devicecomprising: a stationary tank defining a substantially cylindricalinterior space having a larger inner diameter than the cross-sectionaldimension of the barstock material and having an axis; equipment forproducing a water jacket within the interior space and surrounding thebarstock material, said equipment being provided with either at leastone nozzle for injection of water, wherein said nozzle is disposed insubstantially tangential contact with an inner lining of the interiorspace into which it discharges and/or a blade wheel that is disposed soas to rotate about the axis and that is assigned a rotary drivemechanism; and at least one ultrasonic probe connected to the tank andhaving an active face wherein the active face is freely accessible fromthe cylindrical interior space.
 2. The testing device according to claim1, wherein the at least one probe is disposed in such a manner that theactive face thereof is made flush with the inner lining of the tank. 3.The testing device according to claim 1, wherein guide means for thebarstock material are provided, said guide means being devised forguiding a bar of the barstock material to be tested in such a mannerthat the bar is substantially concentric with the axis.
 4. The testingdevice according to claim 1, wherein the tank has two front faces andend rings, wherein the end rings can be replaceably fastened to the twofront faces of the tank and have an opening that is adapted to thebarstock material to be tested.
 5. The testing device according to claim1, wherein the tank has two front faces and a collecting basin isprovided beneath at least one front face of the tank, said basincollecting water exiting said front face.
 6. The testing deviceaccording to claim 1, wherein the tank has an inner lining and an outletis provided on the tank, which outlet is disposed in substantiallytangential contact with the inner lining and in a direction counter tothe at least one nozzle for water supply.
 7. The testing deviceaccording to claim 1, wherein the tank has an inner lining and helicallyoriented guiding plates are provided on the inner lining.
 8. The testingdevice according to claim 1, wherein the tank has an inner lining andtwo front faces, the inner lining tapering from one front face towardthe other front face.
 9. The testing device according to claim 8,wherein the inner lining conically tapers from one front face toward theother front face.
 10. The testing device according to claim 1, whereinthe active face faces the barstock material.